[RFC] WindowMetadata framework fundamentals

[Sebastian Kügler]

On Wednesday, July 13, 2016 5:10:25 PM CEST Thomas Pfeiffer wrote:
> The caveat that writing text into the thumbnail is problematic is a pretty
> big  problem
> from my perspective. For example in a text editor, I don't see how relevant 
> information
> can be represented by a "pretty picture". I'd rather put e.g. the first X 
> characters into
> the thumbnail there, so that even if the document does not have a name yet,
> it can be recognized by its context.
> Or in a terminal I'd show the last output line or something.
> Outside of graphics applications or media players, I don't see how anything 
> without text
> is supposed to transport meaningful information.

These can be conveyed by text properties, though.

> Isn't there any way to work around the DPI problem?

I've thought long and hard about it, one possibility would be to tell the 
client what DPI is expected. The problem is that all the painting takes the 
current screen's DPI and uses that. Shifting a different DPI in there is 
complicated to get right, too complicated that any user of the API will get it 
right.

Text, on the other hand can be filtered, laid out consistently across tasks, 
and can be painted over the preview by the server in the correct DPI. The test 
application contains some example code that overlays the text over the 
thumbnail.

> If not, I'd suggest to allow the application to choose whether it wants a 
> thumbnail or text
> to be shown. Then graphical applications could render a thumbnail, while
> most others would just make it show text.

That's the idea, anyway. Applications don't *have to* supply a thumbnail. All 
of this is optional.

> I'm super-excited to see the window metadata idea come to life, as it
> promises  tons of
> possibilities. It would be sad if we'd limit these possibilities by
> restricting  ourselves to
> "pretty pictures". The goal is to create actually useful thumbnails, after
> all.
> 
> Hope that helps!

It does, thanks.
-- 
sebas

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